1. Field of the Invention
The present invention relates, in general, to a three-dimensional (3D) measurement system and method therefor and, more particularly, to a 3D measurement system and method, which use images captured by projecting a predetermined pattern onto a target object and image information obtained from a plurality of lighting devices.
2. Description of the Prior Art
The exact measurement of three-dimensional (3D) coordinates of a target object in a non-contact manner has been urgently required in all fields needing 3D data and, for this, stereo matching, pattern projection, etc. have been chiefly proposed.
Stereo matching is a method for calculating 3D coordinates using differences between the phases of corresponding points from images of a target object captured by two cameras having different views, and searching for the corresponding points between images is the key to this method. Further, stereo matching using two cameras enables measurement even for a moving image in which a target object is moving, and also enables measurement even if the surface of a target object is continuous, or includes a hidden face. However, a problem arises in that the results of searching for the corresponding points between images captured by two cameras are not reliable, and especially in a case where a target object does not have a characteristic pattern, material or design, matching points cannot be found.
Pattern projection is a method for measuring the distortion of a predetermined pattern by projecting the predetermined pattern onto a target object. Such a pattern projection method exhibits highly-reliable results, but intervals between lines determine the precision of measurement, so that precision is deteriorated, and reliable results cannot be exhibited in the case of a discontinuous surface.